Causal relationship between physical activity and platelet traits: a Mendelian randomization study.

Introduction: The purpose of this study was to discuss the causal relationship between physical activity and platelet traits. Methods: A dataset from a large-scale European physical activity and platelet traits was collected by using Mendelian randomization of the study. For the analysis, the inverse variance weighting method, weighted median and MR-Egger were used to estimate causal effects. The sensitivity analyses were also performed using Cochran's Q test, funnel plots and Leave-one-out analysis. Results: Light DIY, other exercises, strenuous sports, walking for pleasure were significantly associated with a decrease in platelet crit. But none of the heavy /light DIY was associated with increase in platelet crit. Other exercises and strenuous sports were associated with decrease in platelet count. Conclusion: Some types of physical activity have a causal relationship with platelet crit and platelet count. However, the types of physical activity we studied have not supported a causal relationship with mean platelet volume and platelet distribution width.

Photosensitive Hydrogels Encapsulating DPSCs and AgNPs for Dental Pulp Regeneration.

OBJECTIVE: Pulp regeneration with bioactive dentin-pulp complex has been a research hotspot in recent years. Stem cell therapy provided an interest strategy to regenerate the dental-pulp complex. Hence, this study aimed to evaluate the effects of photosensitive gelatin methacrylate (GelMA) hydrogel encapsulating dental pulp stem cells (DPSCs) and silver nanoparticles (AgNPs) for dental pulp regeneration in vitro. METHODS: First, the AgNPs@GelMA hydrogels were prepared by lithium phenyl-2,4,6-trimethyl-benzoyl phosphinate (LAP) initiation via blue-light emitting diode light. The physical and chemical properties of AgNPs@GelMA hydrogels were comprehensively analysed via scanning electron microscopy (SEM), and mechanical characterisation, such as swelling ability, degradation properties, and AgNP release profile. Then, AgNPs@GelMA hydrogels encapsulated DPSCs were used to establish an AgNPs@GelMA biomimetic complex, further analysing its biocompatibility, antibacterial properties, and angiogenic capacity in vitro. RESULTS: The results indicated that GelMA hydrogels demontrated optimal characteristics with a monomer:LAP ratio of 16:1. The physico-chemical properties of AgNPs@GelMA hydrogels did not change significantly after loading with AgNPs. There was no significant difference in AgNP release rate amongst different concentrations of AgNPs@GelMA hydrogels. Fifty to 200 µg/mL AgNPs@GelMA hydrogels could disperse E faecalis biofilm and reduce its metabolic activity . Furthermore, cell proliferation was arrested in 100 and 200 µg/mL AgNPs@GelMA hydrogels. The inhibition of 50 µg/mL AgNPs@GelMA hydrogels on E faecalis biofilm was above 50%, and the cell viability of the hydrogels was higher than 90%. The angiogenesis assay indicated that AgNPs@GelMA hydrogels encapsulating DPSCs could induce the formation of capillary-like structures and express angiogenic markers CD31, vascular endothelial growth factor , and von willebrand factor (vWF) in vitro. CONCLUSIONS: Results of this study indicate that 50 µg/mL AgNPs@GelMA hydrogels encapsulating DPSCs had significant antibacterial properties and angiogenic capacity, which could provide a significant experimental basis for the regeneration of the dentin-pulp complex.

Corrigendum to 'Application of bioactive hydrogels combined with dental pulp stem cells for the repair of large gap peripheral nerve injuries' [Bioactive Mater. 6 (3) (2021) 638-654].

[This corrects the article DOI: 10.1016/j.bioactmat.2020.08.028.].

Application of thermosensitive-hydrogel combined with dental pulp stem cells on the injured fallopian tube mucosa in an animal model.

Objectives: Fallopian tube (FT) injury is an important factor that can lead to tubal infertility. Stem-cell-based therapy shows great potential for the treatment of injured fallopian tube. However, little research has shown that mesenchymal stem cells (MSCs) can be used to treat fallopian tube damage by in situ injection. In this study, we in situ transplanted PF127 hydrogel encapsulating dental pulp stem cells (DPSCs) into the injured sites to promote the repair and regeneration of fallopian tube injury. Materials and methods: The properties of dental pulp stem cells were evaluated by flow cytometry, immunofluorescence analysis, and multi-differentiation detection. The immunomodulatory and angiogenic characteristics of dental pulp stem cells were analyzed on the basis of the detection of inflammatory factor expression and the formation of capillary-like structures, respectively. The biocompatibility of PF127 hydrogel was evaluated by using Live/Dead and CCK-8 assays. The effects of PF127 hydrogel containing dental pulp stem cells on the repair and regeneration of fallopian tube injury were evaluated by histological analysis [e.g., hematoxylin and eosin (H&E) and Masson's trichrome staining, TUNEL staining, immunofluorescence staining, and immunohistochemistry], Enzyme-linked immunosorbent assay (ELISA), and RT-PCR detections. Results: Dental pulp stem cells had MSC-like characteristics and great immunomodulatory and angiogenic properties. PF127 hydrogel had a thermosensitive feature and great cytocompatibility with dental pulp stem cells. In addition, our results indicated that PF127 hydrogel containing dental pulp stem cells could promote the repair and regeneration of fallopian tube damage by inhibiting cell apoptosis, stimulating the secretion of angiogenic factors, promoting cell proliferation, modulating the secretion of inflammatory factors, and restoring the secretion of epithelial cells. Conclusion: In this study, our results reported that in situ injection of PF127 hydrogel encapsulating dental pulp stem cells into the injured sites could provide an attractive strategy for the future treatment of fallopian tube injury in clinical settings.

Titanium Nanotube Modified With Silver Cross-Linked Basic Fibroblast Growth Factor Improves Osteoblastic Activities of Dental Pulp Stem Cells and Antibacterial Effect.

Titanium modifications with different silver loading methods demonstrate excellent antibacterial properties. Yet pure silver nanoparticles with limited bioactive properties may delay regeneration of bone surrounding the dental implant. Therefore, loading silver with bioactive drugs on titanium surfaces seems to be a very promising strategy. Herein, we designed a silver (Ag) step-by-step cross-linking with the basic fibroblast growth factor (bFGF) by polydopamine (PDA) and heparin on titanium nanotube (TNT) as its cargo (TNT/PDA/Ag/bFGF) to improve the implant surface. Our results showed that TNT/PDA/Ag/bFGF significantly enhanced the osteogenic differentiation of dental pulp stem cells (DPSCs). It also showed an excellent effect in bacterial inhibition and a reduction of pro-inflammatory factors through inhibition of M1 macrophage activity. These results showed that bFGF cross-linked silver coating on TNTs presented good osteogenic differentiation and early anti-infiammatory and antibacterial properties. Together, this novel design on titanium provides a promising therapeutic for dental implants.

Effects and mechanisms of basic fibroblast growth factor on the proliferation and regenerative profiles of cryopreserved dental pulp stem cells.

OBJECTIVES: Various factors could interfere the biological performance of DPSCs during post-thawed process. Yet, little has been known about optimization of the recovery medium for DPSCs. Thus, our study aimed to explore the effects of adding recombinant bFGF on DPSCs after 3-month cryopreservation as well as the underlying mechanisms. MATERIALS AND METHODS: DPSCs were extracted from impacted third molars and purified by MACS. The properties of CD146+ DPSCs (P3) were identified by CCK-8 and flow cytometry. After cryopreservation for 3 months, recovered DPSCs (P4) were immediately supplied with a series of bFGF and analysed cellular proliferation by CCK-8. Then, the optimal dosage of bFGF was determined to further identify apoptosis and TRPC1 channel through Western blot. The succeeding passage (P5) from bFGF pre-treated DPSCs was cultivated in bFGF-free culture medium, cellular proliferation and stemness were verified, and pluripotency was analysed by neurogenic, osteogenic and adipogenic differentiation. RESULTS: It is found that adding 20 ng/mL bFGF in culture medium could significantly promote the proliferation of freshly thawed DPSCs (P4) through suppressing apoptosis, activating ERK pathway and up-regulating TRPC1. Such proliferative superiority could be inherited to the succeeding passage (P5) from bFGF pre-stimulated DPSCs, meanwhile, stemness and pluripotency have not been compromised. CONCLUSIONS: This study illustrated a safe and feasible cell culture technique to rapidly amplify post-thawed DPSCs with robust regenerative potency, which brightening the future of stem cells banking and tissue engineering.

Application of bioactive hydrogels combined with dental pulp stem cells for the repair of large gap peripheral nerve injuries.

Due to the limitations in autogenous nerve grafting or Schwann cell transplantation, large gap peripheral nerve injuries require a bridging strategy supported by nerve conduit. Cell based therapies provide a novel treatment for peripheral nerve injuries. In this study, we first experimented an optimal scaffold material synthesis protocol, from where we selected the 10% GFD formula (10% GelMA hydrogel, recombinant human basic fibroblast growth factor and dental pulp stem cells (DPSCs)) to fill a cellulose/soy protein isolate composite membrane (CSM) tube to construct a third generation of nerve regeneration conduit, CSM-GFD. Then this CSM-GFD conduit was applied to repair a 15-mm long defect of sciatic nerve in a rat model. After 12 week post implant surgery, at histologic level, we found CSM-GFD conduit could regenerate nerve tissue like neuron and Schwann like nerve cells and myelinated nerve fibers. At physical level, CSM-GFD achieved functional recovery assessed by a sciatic functional index study. In both levels, CSM-GFD performed like what gold standard, the nerve autograft, could do. Further, we unveiled that almost all newly formed nerve tissue at defect site was originated from the direct differentiation of exogeneous DPSCs in CSM-GFD. In conclusion, we claimed that this third-generation nerve regeneration conduit, CSM-GFD, could be a promising tissue engineering approach to replace the conventional nerve autograft to treat the large gap defect in peripheral nerve injuries.

Biological Behavioral Alterations of the Post-neural Differentiated Dental Pulp Stem Cells Through an in situ Microenvironment.

Transplantation of undifferentiated dental pulp stem cells (DPSCs) may suffer from tumorigenesis. Neuronal differentiated DPSCs (d-DPSCs) have emerged as an ideal source to treat central nervous system (CNS) disorders. Moreover, different components of culture medium functioned on the characteristics of d-DPSCs in vitro. In this study, d-DPSCs were cultured in three types of medium: Neurobasal®®-A medium supplemented with 2% B27 (the 2% B27 NM group), Neurobasal® -A medium supplemented with 2% B27 and 5% FBS (the 2% B27 + 5% FBS NM group), and α-MEM containing 10% FBS (the 10% FBS α-MEM group). We found that d-DPSCs in the 2% B27 + 5% FBS NM group had lower proliferation and reduced expression of transient receptor potential canonical 1 (TRPC1) and CD146, whereas up-regulated Nestin and microtubule-associated protein-2 (MAP-2). Notably, d-DPSCs in the 10% FBS α-MEM group possessed high proliferative capacity, decreased expression of neuron-like markers and partially restored stemness. It was demonstrated that d-DPSCs cultured in the 2% B27 + 5% FBS NM could maintain their neuron-like characteristics. Besides, d-DPSCs cultivated in the 10% FBS α-MEM could partially recover their stem cells properties, indicating that neural differentiation of DPSCs was reversible and could open novel avenues for exploring the pluripotency of DPSCs.

An Evaluation of Norspermidine on Anti-fungal Effect on Mature Candida albicans Biofilms and Angiogenesis Potential of Dental Pulp Stem Cells.

Norspermidine (Nspd) is a kind of polyamine molecule, which is common in eukaryotes and prokaryotes. It has been reported as a potential anti-biofilms agent of bacteria, but its anti-fungal effect remains unclear. Candida albicans (C. albicans) is a common opportunistic pathogen in oral cavity of human beings. C. albicans biofilm is often seen in dental caries. In this work, we aimed to study the effect of Nspd on mature Candida albicans biofilms and to investigate how Nspd would influence human dental pulp stem cells (DPSCs). Our biofilm assays indicated that 111.7 and 55.9 mM Nspd dispersed 48 h mature fungal biofilms and showed significant fungicidal effect. 27.9 and 14.0 mM Nspd showed moderate fungicidal effect. Live/dead staining echoed the fungicidal effect. 111.7-14.0 mM Nspd showed a dose- inhibitory effect on mature fungal biofilm, where 14.0 mM Nspd reduced the metabolic activity by half compared with blank control. Moreover, we demonstrated that 111.7-27.9 mM Nspd restrained the production of hyphae form of C. albicans via SEM. Low dose Nspd (27.9 and 14.0 mM) could significantly reduce virulence related gene expression in C. albicans biofilms. MTT assay displayed a dose effect relation between 2.5-0.08 mM Nspd and DPSCs viability, where 0.63 mM Nspd reduced the viable level of DPSCs to 75% compared with blank control. Live/dead staining of DPSCs did not show distinctive difference between 0.63 mM Nspd and blank control. Vascular differentiation assay showed capillary-like structure of inducted DPSCs culture with and without 0.63 mM Nspd suggesting that it did not significantly affect angiogenic differentiation of DPSCs. Nspd can penetrate remaining dentin at low level, which is confirmed by an in vitro caries model. In conclusion, our study indicated high dosage Nspd (111.7 and 55.9 mM) could effectively disrupt and kill mature fungal biofilms. Low dosage (27.9 and 14.0 mM) showed mild anti-fungal effect on mature C. albicans biofilms. Human DPSCs were tolerate to 0.08-0.63 mM Nspd, where viability was over 75%. 0.63 mM Nspd did not affect the proliferation and angiogenetic differentiation of DPSCs.

Analysis of Flavonoid Metabolites in Chaenomeles Petals Using UPLC-ESI-MS/MS.

Chaenomeles species are used for both ornamental decoration and medicinal purposes. In order to have a better understanding of the flavonoid profile of Chaenomeles, the petals of four Chaenomeles species, including Chaenomeles japonica (RB), Chaenomeles speciose (ZP), Chaenomeles sinensis (GP), and Chaenomeles cathayensis (MY), were selected as experimental material. The total flavonoid content of GP was found to be the highest, followed by MY, ZP, and RB. In total, 179 flavonoid metabolites (including 49 flavonols, 46 flavonoids, 19 flavone C-glycosides, 17 procyanidins, 15 anthocyanins, 10 flavanols, 10 dihydroflavonoids, 6 isoflavones, 5 dihydroflavonols, and 2 chalcones) were identified by Ultra-Performance Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry. Screening of differential flavonoid metabolites showed that GP had higher levels of metabolites when compared with the other three Chaenomeles species. Annotation and enrichment analysis of flavonoid metabolites revealed that cyanidin 3,5-diglucoside and pelargonidin-3,5-diglucoside anthocyanins are likely responsible for the color differences of the four Chaenomeles petals. Additionally, a large number of flavonoids, flavonols, and isoflavones were enriched in the petals of GP. This study provides new insights into the development and utilization of Chaenomeles petals and provides a basis for future investigations into their utilization.

Research and application of stem cell ⁃ derived exosomes in regenerative medicine / 口腔疾病防治

@# Stem cells are a class of undifferentiated cells with high self⁃renewal and rapid proliferative capabilities. Undercertain conditions, stem cells can induce differentiation into other tissue cells of the human body, such as skeletal muscle cells, cardiomyocytes, osteoblasts, and nerve⁃like cells. In recent years, with the development of tissue engineer⁃ ing and regenerative medicine, stem cells have been extensively used in various fields of regenerative medicine as opti⁃ mal seeded cells; however, there are still some problems, such as the decreased cell survival rate and regenerative ca⁃ pacity after transplantation, immune rejection, and ethical supervision. Therefore, it is difficult to universally and safely use stem cell banks for regeneration applications. The paracrine effect of stem cells has been extensively studied since its discovery. Increasing evidence supports the view that stem cells act in paracrine manner, and the secretion of exo⁃ somes plays a vital role in their biological functions. Exosomes are nanoscale extracellular vesicles containing biological⁃ ly active molecules such as RNA and proteins; they possess similar functions to stem cells and play important roles in cell communication, immune response, and repair of tissue damage. At present, clinical studies on stem cell exosomes in tissue engineering and regenerative medicine have also been carried out in the fields of bone and cartilage repair, nerve tissue regeneration, liver tissue regeneration, skeletal muscle tissue engineering, vascular regeneration, taste bud repair, tooth regeneration, etc. In this paper, the composition, formation, release and identification of exosomes are intro⁃ duced in detail. The research status of exosomes from different stem cell sources in tissue engineering and regenerative medicine is described, and their broad application prospects are discussed.